Control valve and process control system

ABSTRACT

The control valve has a stator which imparts a swirl to the flow of fluid and a rotor which is rotated under the swirl of fluid. Energy is absorbed from the rotor in various ways. In one instance, the rotation of the rotor is subjected to a drag force which is induced in opposition to the force of rotation in order to control the pressure drop in the flow. In another instance, the rotation of the rotor is used to store electrical energy which can be used for other purposes throughout the process system.

[75] Inventor:

States Patent [191 OConnor, Jr.

[11 3,709,245 Jan. 9, 1973 [54] CONTROL VALVE AND PROCESS CONTROL SYSTEMJoseph OConnor, Jr., Goshen, NY.

[73] Assignee: Kieley & Mueller, lnc., Middletown,

['22 Filed: Feh. 5,1971

21 Appl. 1%.: 112,890

[52] 'U.S. Cl ..25l/l27 [51] Int. Cl F1611 47/00 [58] Field of Search..4l5/l57, 158; 251/117, 118,

[56] 7" References Cited UNITED STATES PATENTS 2,415,670 2/1947 Blacketal ..230/114 ux 12/1959 Weis ....4l5/l57 4o ll FOREIGN PATENTS 0RAPPLICATIONS 101,361 4/1962 Netherlands ..415/l57 Primary Examiner-HenryT. Klinksiek Assistant ExaminerRobert J Miller Attorney-Kenyon & KenyonReilly Carr & Chapin {57] ABSTRACT 9 Claims, 6 Drawing Figures 1 How byPATENTEUJAN 9 ms 3.709.245 SHEET 1 [1F 2 INVENTOR. JOSEPH O Co--on JR.

PATENTEDJAN 9 I975 SHEET 2 0F 2 li E INVENTOR.

JOSEPH O'Co/yNoQ,Jn.

i g, T a I Arm/v.

CONTROL VALVE AND PROCESS CONTROL SYSTEM This invention relates to acontrol valve and a controlled process system.

Heretofore, various control valves have been known for creating anenergy loss or pressure drop for process control within a processsystem. For example, the energy loss or the pressure drop has beenaccomplished by the impingement of the fluid flow on inner valvesurfaces, by turbulence, by self-impingement, and by impingement uponvalve, body and closely associated piping surfaces. However, thesecontrol valves for process control have been inherently self-destructivesince the constant erosive and cavitation effects of high velocityfluids upon the control valve, inner valve bodies and associated pipingsurfaces eventually wears out the valve. Further, by the very nature ofthe energy loss, the total enthalpy of a process is changed, that is,the control valve by its nature does remove, a certain percentage, e.g.,20 percent, of the total process energy imparted'to a process. Thisremoved energy has heretofore been unrecoverable.

It has also been known that various valve devices have utilized a rotorfor measuring or indicating the amount. of flow or flow velocity of afluid, passing through a valve. These valve devices have, however,merely been used as measuring devices and have not controlledthepressure drop in the flow of fluid. Instead, the measuring deviceshave been constructed so as to achieve a minimum of pressure drop.

Accordingly, it is an object of this invention to utilize the energynormally lost within a control valve, while retaining the flow controlcharacteristics of a flow control valve.

It is another object of this invention to eliminate the erosive andcavitation effects of a pressure drop of a fluid within a control valve.and to reduce noise generated bya-fluid within a control valve.

it is another object of this invention to provide a control valve ofsimple construction for the elimination of erosive effects due to theflow of fluid therethrough.

it is another object of this invention to recover some percentage of theutilizable energy lost within a control valve so as to improve the totalefficiency for a given process.

Briefly, the invention is directed to a control valve which accomplishesuseful work while creating an energy loss or pressure drop in a fluidpassing therethrough. In addition, the control valve is interconnectedwith various other components within a process system so that the energyobtained within the control valve can be used to operate these othercomponents. In this way, the invention utilizes at least a part of theenergy transformed in creating a pressure drop within a fluid flowingthrough the process system such that the overall efficiencyof the systemis increased.

The control valve includes a housing which is positioned to define apassageway for a flow of fluid, a stator which is mounted within thehousing and a rotor which is mounted within the stator so as to rotateunder the flow of fluid passing to the rotor from the stator. ln oneembodiment, the rotor is concentrically mounted within the stator and isaxially movable with respect to the stator so that the amount of flow offluid passing through the rotor can be varied. The rotor is also movableinto a closed position in which the passageway for the flow of fluid isclosed so that no fluid can flow through the control valve. In addition,a work useless means such as a drag inducing means is connected to therotor so as to induce a drag force on the rotor under the flow of fluidto create a controlled pressure drop in the fluid flow.

in operation, during the induced rotation of the rotor, work is createdfrom the energy transference which energy transference is a function ofthe engagement of the rotor within the stator. This work is thenabsorbed in the drag element. In addition, the drag element can beexposed to ambient temperatures in case high temperatures are generatedwithin the drag element so as to improve energy dissipation.

In another embodiment wherein the rotor is axially movable with respectto the stator, the rotor is connected to a generator of the directcurrent type of alternating current type. The rotor is then used togenerate an electrical charge in proportion to the rotational speed ofthe rotor under the influence of the fluid flow. The electrical energywhich is so generated can either be stored in a suitable storage deviceor can be directed to another component within the process system.

In still another embodiment, the rotor is mounted in a fixed axialposition with respect to the stator so that the entire flow of fluidpassing from the stator is directed through the rotor. in thisembodiment, the rotor can be connected to a suitable electrical storagedevice so as to obtain energy or can be connected to a suitable motorfor speed control. In the first instance, where the rotor is connectedto an electrical storage device to store energy, the rotor is directlyconnected through suitable electrical means such as brushes so as toimpart a charge to the storage means. In the case where the rotor isconnected to a motor, a coil is mounted about the rotor and a current isinduced in the coil from the motor so as to impart a rotational force tothe rotor in opposition to the direction of rotation imparted by thefluid flow. In this way, the electro-magnetic system is used to controlthe speed of the rotor and thus the pressure drop in the fluid flow. Inaddition, this embodiment as in all electrical embodiments describedherein can be made explosion proof and can be connected into a processcomputer which could command the pressure drop or flow.

in these various embodiments, the fluid flow first enters into thecontrol valve and is thereafter divided upon impingement on the stator.In addition, the flow is passed circumferentially about the stator sothat a substantially uniform distribution of the fluid flow is passedthrough the stator. The flow is thereafter directed against the rotor soas to induce a rotary motion in the rotor. Upon passing through therotor, the fluid flow impinges upon itself and passes out of the rotorin a direction vertical to the rotor rotation. Thereafter, the fluidflow passes out of the control valve.

In still another embodiment, the control valve is modified so as to actas a process flow meter. In this embodiment, a coil is attached to therotor-to induce direct current bits or intermittent signals which arecalibrated as a measure of the rotation of the rotor. In addition,suitable pressure differential measuring devices are located at theinlet and outlet of the control valve to obtain pressure values at thesepoints and a means, such as a linear resistance potentiometer, is

connected to the valve to measure the opening between the engagement ofthe rotor and stator and obtain a signal characteristic thereof. Thebits or signals, etc. from the coil, the measure pr'essurevalues fromthe measuring devices and the signals characteristic of the openingbetween the rotor and stator are fed into a computer and analyzedtherein ina suitable fashion so that an instaneous readout of the flowpassing through the control valve is obtained.,The computer can also beprogrammed to effect changes in the rotor position in response tovarious obtained readouts so as to permit automatic control of thevalve.

The process system according to the invention utilizes the control valveas described above in a fashion such that the energy which is lost dueto the pressure drop is partially recovered in the form of work so as tooperate various other components in the process system. For example,where the system includes an installation which feeds a flow of fluidinto a pipeline in which the control valve is located as well as afeedpipe for supplying a working medium to the installation, the controlvalve is connected to anfelectrical generator so that the work performedby the rotor induces an electri cal charge in the generator which isused to operate a further valve in the feedpipe to control the quantityof working medium delivered into the installation. The energy whichis'recovered by the control valve of the invention can, however, beused forany suitablepurpose within the'pr'ocess system other than thatexamplefied. In this way, the overall efficiency of the process systemcan be significantly increased.

It is noted that the control valve of the invention can be used inprocesssystem so as to recover a substantial portion ofthe energy whichwould otherwise be lost. For example, ina conventional process systemwherein 20 percent of the energy imparted to the system may be used forpurposes of control with a resulting efficiency of 80 percent, a portionof this '20 percent loss can be recovered by the invention. For example,25 percent or more, that is, percent or more of the total energy, can'be recovered in the control valve of the invention. The

recovered energy can thenbeused to control various other componentsthrough the system. Thus, instead of the process system having anoverall efficiency of 80 percent, the efficiency can be increased to 85percent or more. This willlimpart a significant savings in the overallcost of operation of process systems.

These and other objects and advantages of the invention will become moreapparent from the following detailed description and appended claimstaken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a cross-sectional view of a control valve'within' apipe line according to the invention;

FIG. 2 illustrates a view-taken on line 2-2 of FIG. 1;

FIG. -3 illustrates a perspective view of a rotor and drag elementaccording to the invention;

FIG. 4 illustrates a rotor as in FIG. 1 further provided with a meter;-

7 FIG. 5 illustrates a further modification according to the invention;-and r FIG. 6 illustrates a schematic view of a process systemincorporating a control valve according to the invention.

Referring to FIG. 1, the control valve 10 is interconnected within apipeline 11 so as to intercept a flow of fluid passing through thepipeline 11. The control valve 10 includes a housing 12 having an inlet13 on one side and an outlet 14 on the opposite side with the outlet 14being disposed in a different plane from the inlet 13. In addition, anaperture 15 is disposed within the housing 12 between the inlet 13 andoutlet. 14 for the flow of fluid therethrough. A stator 16 is mountedwithin the housing 12 and includes a plurality of stator blades 17 whichare disposed in transverse relation to the flow of fluid passing intothe inlet 13 of the housing 12. The

' uniform flow of fluid passes into the stator interior. The

lowermost ring 18 as shown, of the stator 16 is constructed as a seatring and is seated about the aperture 15 of the housing 12. In addition,a rotor 19 is 'concen trically mounted within the stator 16 and isaxially movable with respect thereto.,The rotor 19 includes a rotor cage20 which is formed of a plurality of rotor blades 21, a ring 22 in'whichthe blades 21 are mounted at the lower ends and a sealing disc 23 inwhich the blades 21 are mounted at the upper end. The rotor blades 21are substantially parallel to the stator blades 17 and are aligned withrespect to the rotor axis and the stator blades 17 so that the fluidflows passing from the stator 16 impinge'on the rotor blades 21 toimpart a rotary motion to the rotor 19. In addition, the rotor 19includes a rotor shaft 24 which is secured to the sealing disc 23andwhich passes upwardly out of the plane of the stator 16.

The sealing disc 23 is provided with a bevelled surface 25 to mate witha corresponding bevel surface 26 on the seat ring 18 of the stator 16when the rotor 19 is moved into a closed position. In this position, thesealing disc 23 sealingly seats on the seat ring 18 so as to close offany flow of fluid through the control valve'10.

In order to move the rotor 19 axially with respect to the stator 16, therotor shaft 24 is connected via a thrust bearing 27 to a stem 28 whichpasses upwardly out of the valve housing 12. This stem 28 is of anysuitable known construction and can be connected to a hand wheel 29 formanual operation or an auxiliary power operated device such as adiaphragm motor actuator, electric motor actuator .or piston actuator,which positions the rotor within the stator in accordance with areceived signal for automatic opera tion of the valve 10. Forexample,'the valve stem 28 is threadably mounted within the valvehousing 12 so as to be moved longitudinally into or out of the housing12 upon rotation. I

In order to induce a drag force on .the rotor 19, a chamber 30 issecured to the lower end of the valve stem 28 to define a space for aviscous fluid or liquid 31. In addition, the chamber 30 is provided witha recess 32 at the upper end and the rotor shaft 24 is provided with athrust plate 33 which fits into the recess 32 while a plurality ofroller ball bearings 34 are disposed between the chamber 30 and thrustplate 33 to form the thrust bearing 27. In addition, a plurality ofpaddles 35 or other suitable members are secured to the rotor shaft 24within the chamber 30 to rotate within the viscous fluid 31 in thechamber 30 upon rotation of the shaft 24 to impart a drag force on therotor shaft 24. The chamber 30 is also provided with a plurality ofradiating fins 36 which act as heat dissipating means for any heat whichis developed within the chamber 30 as well .as with a sealing ring 37 atthe lower end to prevent passage of the viscous fluid 31 out of thechamber 30 along the rotor shaft 24.

In order to secure the valve stem 28. to the chamber 30, the lower endof the valve stem 28 is provided with a flanged portion 38 which issecured as by threading into the recessed portion 32 of the chamber 30over the flanged plate 33 of the rotor shaft 24. In this way, thediameter of the valve stem 28 can be made with a reduced size.

In addition, a suitable pressure measuring means 39 is connected to thevalve to measure the pressure drop through the valve 10. The pressuremeasuring means 39 includes a pressure measuring tube 40 at the inlet 13to the housing 12 and a similar tube 41 at the outlet 14 for measuringthe pressure thereat and a suitable means 42 connected to the tubes 40,41 for measuring the difference in pressure.

In operation, a flowof fluid passes from the pipeline 11 into thehousing 12 through the inlet 13 and passes circumferentially about thestator 16. At the same time, the flow passes between the blades 17 ofthe stator 16 and are directed to impinge upon the rotor blades 21 so asto impart a rotary motion to the rotor 19. Upon passing through therotor blades 21, the fluid flow impinges upon itself and is directeddownwardly, that is, perpendicularly'to the original path of flow intothe housing 12 so as to flow through the aperture 15 leading to theoutlet 14 of the valve housing 12. As the rotor 19 is forced to rotateunder the action of the fluid flow, the paddles 35 within the chamber 30are moved through the fluid 31. However, since the fluid 31 resists therotation of the paddles 35, a drag force is imposed on the rotor 19 inopposition to the rotary force imposed-by the fluid flow. As a result,the rotor 19 resists the fluid flow so that a pressure drop is imposedupon the flow of fluid passing through the rotor 19.

In order to vary the amount of pressure drop for a given flow, the rotorcage is raised or lowered within the stator 16 by means of the handwheel 29 or automatic actuator.

In order to close, off the flow of fluid through the control valve 10,the'hand wheel 29 or automatic actuator is operated until the sealingdisc 23 of the rotor 19 seats on the seat ring 18 of the stator 16.Alternatively, in order to permit the entire flow of fluid to passthrough the valve 10 without a change in pressure, the handwheel 29 orautomatic actuator is operated so that the rotor 19 is retractedcompletely from within the stator 16 or to a maximum position to permita standard energy loss to be obtained for the control valve purpose.

Referring to FIG. 4, wherein like reference charac- 24 and, thus, theamount of opening between the rotor 19 and stator 16. In addition, apick-up or counter means 44 is connected electro-magnetically, orotherwise, to the rotor shaft 24 to measure the speed of the rotor 19 bycounting the number of revolutions of the rotor shaft 24. For example, acoil is attached to the rotor shaft 24 to produce or induce directcurrent bits with the engagement of the rotor in the stator which arecalibrated as a measure of the rotation of the rotor 19.

Also, a computer 45 of known construction is connected to the metermeans 43 and counter means 44 to receive the signals from theserespective means 43, 44 characteristic of the rotor position and speed.Still further, the pressure measuring means 42 (FIG. 1) is connected tothe computer 45 to deliver a signal thereto characteristic of thepressure drop across the valve. The computer 45 receives the informationfrom these three means 42, 43, 44 and analyzes and compares theinformation with predetermined information so as to indicate the flowpassing through the control valve at any instant in time.

In operation, the valve, in addition to obtaining work as abovedescribed, can be automatically operated by a suitable programming ofthe computer 45 in response to the signals received from the meter 43,counter 44 and pressure measuring means 42 so as to actuate an actuator,as above described, connected to the valve stem 28. This would permitthe valve to be incor. porated in a fully automated control system.

Referring to FIG. 5, wherein like reference characters are used -toindicate like'parts as above, an electromagnetic means 46 is used toimpart a drag force on the rotating rotor 19. To this end, a magnet '47is fixedly secured on the rotorshaft 24 and a pair of coils 48 aredisposed on opposite sides of the magnet 47. Each of these coils 48 isconnected to a suitable electrical device 49 such as a variable DC motorso as to receive a current therefrom. Upon receiving a predeterminedcurrent, a magnetic field is induced by the coils 48 which causes themagnet 47 and thus, the rotor 19, to rotate in a direction opposite tothe flow induced rotation. Thus, during operation, as the motor 49 canbe controlled, the drag force can be controlled so that theelectro-magnetic means 46 imposes a controlled force on the rotor shaft24 to reduce the speed of rotation of the rotor 19. The remainder of thecontrol valve and the operation thereof is similar to that describedabove and need not be repeated.

Alternatively, in order to obtain electrical energy from the workcreated by the rotor 19, the motor 49 is replaced by a generator such asa direct current or an alternating current generator. ln'this way, therotation of the rotor 19 creates electrical energy in the generator 49which energy can be used for any suitable purpose such as for storage ina battery.

Referring to FIG. 6, a process system which includes, for example, aninstallation 50 for delivering a flow of fluid such as steam into a pipeline 51 has a control valve 52 as described in FIG..5 therein. Thissystem 50 utilizes the energy obtained by the control valve 52 forcontrolling other components in the system. For example, a' feed pipe 53which is connected to the installation 50 to supply a working mediumsuch as feed water is provided with a constant or variable speed pump 54which is electrically connected to an electric storage device 55 so asto receive energy for operation of the pump 54 to regulatethe flow offeed water passing to the installation 50. A suitable heating coil 56 isalso located within the installation 50 and is supplied with a heatingmedium via a pipe line 57 which also has a valve 58 therein. This valve58 is regulated or operated by a suitable temperature controller 59, asis known, in

- response. to the temperature of the feed water in the installation 50.1 v

In addition, the control valve 52 which is connected with a generator60, as above described, to deliver electrical energy to the storagedevice 55 is also connected to a pressure controller 61 as is known.This pressure controller 61 serves to measure the vapor pressure in theinstallation 50 and to regulate the control valve 52 in response tosuchvapor pressure. 7

In operation, as steam is generated and delivered through the pipe line51 to a consumer (not shown), the control valve 52 is set to maintain apredetermined pressure drop in the flow. At the same time, the controlvalve 52 is able to obtain work from the steam flow and to convert thiswork via the generator 60 into electrical energy which isstored in thestorage device 55. Should the system require a change in the rate offeed water input, the pump 54 is actuated via the electrical energystored in the storage device 55 to increase or decrease the feed waterinput. I

The invention thus provides a valve which utilizes the work created ineffecting a pressure drop in a fluid flow so as to eliminate the erosiveand cavitational effects of the pressure drop of the fluid. Byredirecting the fluid flow in the pattern described above through thestator and rotor; there is a reduction in the wear and tear on theoverall control valve.

Further, the invention provides a control valve which when used incombination with a generator is able to recover a percentage of theenergy lost in controlling the pressure drop in the fluid flow so as toimprove the total efficiency ofthe given process.

' -What is claimed is:

l. A .control valve comprising a housing defining a passageway for theflow of a fluid and a means in said passage defining an aper ture forthe flow of fluid;

a stator mounted within said housing upstream of said means in the pathof flow of the fluid to impart a swirl to the fluid passingtherethrough;

a rotor rotatably mounted between said stator and said means in the pathof flow of the fluid for rotation under the flow of fluid passingtherethrough;

5 means for moving said rotor relative to said stator to vary the flowof fluid passing through said 'rotor from said stator; and

means for inducing a drag force on said rotor to slow the rotation ofsaid rotor and obtain a controlled pressure drop in the flow of fluid.

2. A control valve as set forth in claim 1 wherein said rotor isconcentrically mounted within said stator. I

3. A control valve as set forth in claim 1 wherein said stator ismounted in said passageway in transverse relation to the path of flow toimpart a circumferential swirl to the flow of fluid passingtherethrough.

4. A control valve as set forth in claim 1 wherein said means in saidpassage is a seat ring and said rotor includes a sealing disc having asurface t hereon for mating with said seat ring in a closed position ofsaid rotor to seal said aperture of said seat ring to the flow of fluid.1 v

5. A control valve as set forth in claim 1 wherein said rotor includes arotor cage having a plurality of blades disposed within said stator andsaid stator includes a plurality of blades for directing the flow offluid onto said blades of said rotor.

6. A control valve as set forth in claim 5 wherein said rotor furtherincludes a rotor shaft extending from said cage and wherein said meansfor inducing a drag force includes a chamber about said rotor shaftdefining a space for a viscous liquid therein and a plurality of paddlesmounted on said rotor shaft within said chamber for rotation in theviscous liquid therein.

7. A control valve as set forth in claim 6 further comprises means fordissipating heat from said chamber.

8. A control valve as set forth in claim 7 wherein said latter meansincludes a plurality of fins extending from said chamber.

9. A control valve as set forth in claim 5 wherein said means for movingsaid rotor includes a rotor shaft connected to said cage, alongitudinally movable valve stem extending from said rotor shaft and athrust hearing securing said rotor shaft to said valve stem for relativerotation therewith.

1. A control valve comprising a housing defining a passageway for theflow of a fluid and a means in said passage defining an aperture for theflow of fluid; a stator mounted within said housing upstream of saidmeans in the path of flow of the fluid to impart a swirl to the fluidpassing therethrough; a rotor rotatably mounted betwEen said stator andsaid means in the path of flow of the fluid for rotation under the flowof fluid passing therethrough; means for moving said rotor relative tosaid stator to vary the flow of fluid passing through said rotor fromsaid stator; and means for inducing a drag force on said rotor to slowthe rotation of said rotor and obtain a controlled pressure drop in theflow of fluid.
 2. A control valve as set forth in claim 1 wherein saidrotor is concentrically mounted within said stator.
 3. A control valveas set forth in claim 1 wherein said stator is mounted in saidpassageway in transverse relation to the path of flow to impart acircumferential swirl to the flow of fluid passing therethrough.
 4. Acontrol valve as set forth in claim 1 wherein said means in said passageis a seat ring and said rotor includes a sealing disc having a surfacethereon for mating with said seat ring in a closed position of saidrotor to seal said aperture of said seat ring to the flow of fluid.
 5. Acontrol valve as set forth in claim 1 wherein said rotor includes arotor cage having a plurality of blades disposed within said stator andsaid stator includes a plurality of blades for directing the flow offluid onto said blades of said rotor.
 6. A control valve as set forth inclaim 5 wherein said rotor further includes a rotor shaft extending fromsaid cage and wherein said means for inducing a drag force includes achamber about said rotor shaft defining a space for a viscous liquidtherein and a plurality of paddles mounted on said rotor shaft withinsaid chamber for rotation in the viscous liquid therein.
 7. A controlvalve as set forth in claim 6 further comprises means for dissipatingheat from said chamber.
 8. A control valve as set forth in claim 7wherein said latter means includes a plurality of fins extending fromsaid chamber.
 9. A control valve as set forth in claim 5 wherein saidmeans for moving said rotor includes a rotor shaft connected to saidcage, a longitudinally movable valve stem extending from said rotorshaft and a thrust bearing securing said rotor shaft to said valve stemfor relative rotation therewith.